Limit stop mechanism for poweroperated gun mounts



Sept. 27, 1949.

P. E.` HUMPHREY LIMIT STOP MECHANISM FOR POWER OPERATED GUN MOUNTS Filed Jan. 30, 1947 /d M m.. Nl E Wy L5 IH f.

Patented Sept. 27, 1949 :LIMIT :ST O1 MECHAN ISM Y FR :POWER- QPERATED GUN. MQUNTS the Secretarymf War Applicatiomanuaryso, 19'47,seria1fNo. 725,194

The invention described Yirereirrmaydoe manuactured andV used by 'or `for the Government for governmental 'purposeswithout payinent'to me of anyroyalty'thereon.

Thiszinvention relates to contourfollowers and has -special reference Jto the iapplicationof .a device of 'this kind to "an'aircraft gun mount.

Gun mounts .to 'which .this device is applicable are usually rotatablein .azimuth forzthe 'full three hundred 'sixty degrees and in elevation from slightly `below 'the horizontal Vto substantially vertical, Li. e., from several degrees -downre to ninety vdegrees upre.

There are, however, someg'positions in azimuth in 'which the guns 'could fnot be fired, A'if -pointed lower than several degrees upf-ire, without striking vulnerable 'parts of the 'craft upon which they are mounted. In certain military aircraft, for instance, the guns, when pointed aft, :could not be trained much .lower -than six degrees upre before the "line of re 'would "pass through `'the upper .jgunnersfsighting station.

Itstherefore va principal object of this inven- 'tionLto provide mechanism which 'willl'imit to .a

safe angle the declination ofthe line 'of fire of the guns "in any azimuth position.

More specicallystated, 'an object 'is to 'provide a mechanical limiting means 'forarre'st'ing gun declination together 'with 'means to move .said limiting 'meansto diierent-positionsas a result of changing the *line of `fire 'in azimuth.

Anadditional objectofthe invention -is to pro; vide a device Whichis adapted to'interrupttthe power crcuitby which thegunsare-being moved ever the guns are trained so that 'the ring "line passes through any .portion of 'the craft .upon which the device is'be'ing used.

Another object is to provide meansto mechanically disconnect the `power means .which operates 'the gun .elevating meanscoincidentally with Vthe .breaking 4of .the power Ycircuit and the rng circuit.

Another object 'is to provide means Ato cushion the inertia forces Yof the `guns when they strike the azimuth adusted stop whichdetermines the limit of declination of the line of Tire.

-Other objects and advantages will .be .evident upon consideration of fthe following .description when read with reference tothe drawings, .wherein the single figureof'the drawingisa schematic view .in ,perspective `of .an embodiment .of ,my invention. l

Referring to -the drawing, :a .horizontally .disf

2 the turret supporting vframe y(not shown), and has-'internalhteeth I'Zvvhichmay preferably extend completely yaround'tlre'inside ofthe ring.

A reversible 'motor H *is carried by the revolvafble'xturretand has a pinion 13 in mesh with the teeth 12,'whereby rotation ofthe motor H revolves the turret in azimuth. :Motor l"| is 4operable in either direction 'by 'am'eans which, for purposes -o'f illustration only, is herein'shown as a double-throw .switch l1.

A-vertically disposed' ring il# Yalso carried by the revolvingturret 'has a toothed gear segment :16 which needs extend onlypart way around Vthe ring. Rotation of the ring T4 in one or the `other direction'points the 'guns l5 on "the turret at an upward Oria downward angleas required.

Aireversble motor '.IB'is provided to .rotate 'the ring Hlbymeans of a pinon'mLfidler 22, 4gear2`4, shaft.. and gear 28. Motor I8 is operable n either direction .by a means which, forpurposes of illustration only, herein 'shown as a doublelthrow switch 30.

-vThe motors l1 and T8 and theirvcircuits, the-ring gears I0 and I4 and connecting `gears .13, 2U, 22, 2i fand '28 are schematic 4representations .of the structures .in conventional use on aircraft gun 'turrets and are .ltheparts which mustbe usedin combination with my invention to achieve the objects set forth.

`.'Ihe ring .I'4 is shownin the .position which `it assumes when the guns .are pointedatapproximately five ,degrees tupf-ire. .'When .the guns are pointed substantially .in a vertical direction, the

` i Yupperend ofthe gear-.segment 1.6 will be located in declinationas well as the firing .circuit when# in lthe position shown J by `.the .dotted line .32.

.A .pinion f3.4.at the lower `endt-of 1.a -vertical .shaft 36 engages .the .teethtlof .thering gear l0. The upper end of the shaft .is provided `with a'bevel pinion 38 ,Whichris in mesh with-.abevel `gear All carried 4on .the :outer .end ffof the horizontally extending. shaft .42. .A pinion-.44 ifast-.onthercar end ofthe shaft A2,.,meshes'with .three'idler pinions d6 which in .turn mesh with -.the 4internal ring gear .68. Pinions A6 rotate -`on fstuds f5!! which arefast on a nonrotatabl'e frontcover plate which may be .part of .the-,casing fwithin .which the Vgear set `is housed. .'lhe-.nonrotatableffront cover-.plate which =.the .studs -50 has been removed Ymo show the .gear set more :,clearly.

posed ring gear l0 is nonrotatably carried by 55 'Ilhe .ring gear 4.8 Yis fastfon'the `forward end ylof a `shaft .52, the rearward end `of this shaft being provided with .'acam .54 .which `is adapted vto engage a `roller .56 which V.is pivotally .supported :in a slot 58 in lever 60 by a pin 62. The cam '5A thus forms a iulcrum of adjustable height upon which the lever 60 may rock, the height of the fulcrum depending on the position in azimuth to which the turret has been turned with respect to the nonrotatable ring gear I0. The upper or power end of the lever is slotted clevis fashion at 04 for the rod end 60 which is hingedly connected to the lever by the pin 68. The rod which carries the rod vend 68 at one end carries a clevis 12 at the other. The limbs of the clevis 12 are relatively far apart so that the gear segment I6 may pass freely between the limbs when the end of the segment moves from a lower position, as for instance the position 32, to the position shown in the drawing.

The upper end of the segment I8 is provided transversely with a half round groove 14 which engages the clevis pin 18, which is fast in the clevis 12, when the segment is near the end of its travel in the direction of the arrow 18. The clevis pin 10 is prolonged rearwardly beyond the clevis as at 80 so as to be supported in an arcuate slot 82 formed in a guide member 84 which may be a part of the turret frame (not shown) or may be attached thereto. The pin extension 80 and slot 82 maintain the clevis 12 always in a position for re-engagement by the segment I8 lwhen the end of the segment I8 retires from the posiytion shown in the drawing to the position 32 or to some position intermediate the position 32 and the position shown.

The lower or work end of the lever 60, like the upper end, is slotted clevis fashion as at 80 to allow the rod 88 to pass freely through the slot. A vhinge pin 98 passes through the clevis limbs and through the rod 88. The rod 88 is slidable axially in bearings 92 and 94 carried by the turret frame. A relatively heavy compression spring 95 is interposed between the lower end of the lever 60 and the bearing 94. A head 86 may be provided on the rod 88 to limit its travel in the direction of the arrow 98, or the head 96 may be omitted and the spring 95 itself will act as a stop when compressed to the extent that the coils contact each other.

An arm |00 is pinned to the rod 88 so as to move with the rod when the rod moves axially, the outer end of the arm being provided with an opening for slidably receiving the rod |02. A collar |04 is fast on the rear end of the rod |02 and a cushioning spring |08 is held under slight compression between the collar and the arm |00.

The forward end of the rod I 02 carries a clevis |08 between the sides of which the power end of a lever II is hinged by a pin |I2, the work end of the lever III) being adapted to operate the push rod |I4 of a relay IIS, whereby the firing circuit I I8 and the circuit |20, Vwhich controls the operation of the motor I8 in one direction of rotation, may be interrupted.

The lever IIO is pinned to the vertical shaft |22 upon which it fulcrums, whereby operation of the lever III) by axial movement of the rod |02 in the direction of the arrow 98 rocks the shaft through a relatively small angle. A clutch shifting fork |24 fast on the upper end of the shaft |22 is provided for operating a friction clutch I 26 which, when disengaged, prevents rotation of the shaft 26 by the motor I 8. A battery |28l supplies the current for the several circuits. A switch |30 operates a relay |32 for closing the firing circuit. It should be kept in mind that the entire mechanism shown in the drawing is mounted on and revolves With the turret except the ring gear I0 which is nonrotative.

It is noted that the electric circuits with their switches and relays are merely schematic; for instance, the manual switches I1 and 30, for controlling rotation of the motors II and I8 are usually, in actual practice, replaced by automatic controls operated by the sighting mechamsm.

The drawing shows the condition Which the device assumes when the guns are pointed directly aft and the line of nre is adjusted to about five degrees upfire which is the low limit for this azimuth position necessary to avoid firing through the upper gunners sighting station.

For illustrative purposes it may be assumed Athat the guns, both in azimuth and in elevation, are pointed in some other direction than the direction shown. The procedure to accomplish the condition shown in the drawing is substantially as follows:

The motor II is rotated until the turret and the entire mechanism Yherein disclosed, except the ring gear I0 which is nonrotatable, is rotated' to the position of the drawing. VIn so rotating the mechanism, the pinion 34 rolls in the teeth I2 of the ring I0, thereby turning the shaft 38, bevel gears 38 and 40,*pinion 44, idlers 48, ring 48, shaft 52 Vand Vcam 54.V `When the guns point directlyaft, the Vcam will be in the position shown, i. e., with the highest point on the roller 58.' Thereafter, or simultaneously with this azimuth'rotation, the motor I8 is actuated and gear segment .I6 `rotated in thedirection of the arrow 18 to bring thefguns down and the end 32 of the segment I8 up until the half round groove 14 engages the clevis pin 16 and carries it forward, pulling thefrod 10 with it in the direction of the arrow |34, thus rocking the lever on its fulcrum, which, in this vazimuth position, is the high point on the cam 54. The upper end of the lever 60 will continue to move in the direction of the arrow |34 until the head 96 of the rod 88 strikes the Ybearing 92 orY until the spring 95 comes solid. At this stage the pin may be considered the fulcrum; the pin 68, the point of application of the force; and the cam 54, the adjustable stop which limits rotary movement of the segment I6, and consequently, limits gun declination. Obviously, any stop which is automatically adjustable to vary gun declination asa function of turret rotation in azimuth will be considered within the scope of the invention. Y It is noted that while further downward tilting of the guns is always prevented when the head 96 strikes the bearing 92 orwhenv the spring comes solid, the point at which this takes place depends on how high a fulcrum is being provided by the cam 54 and this depends on lthe position of the turret in azimuth, i. e., if the turret had been turned until the guns had pointed forward, the low insteadtof the high side of the cam 54 would have provided the fulcrum and the rod 10 would have moved farther inthe direction of the arrow |34, whereby the Vguns may have stopped their downward tilting movement at five degrees downre as'seen at |36 instead of six degrees upre as seen at I5. v

Movement of the rod 88 to its stop position vsimultaneously moved the arm |00, rod |02 and the lever II8 thereby to operate the relay IIB and thereby break the relay circuit ||8 which disconnected the firing circuit, operation of the relay at the same time disconnecting that side of the circuit of the motor I8 which moved the guns in declination. The same move-- assises?) ment of the =r`od IBB in the .direction of the arrow 3B also .operated .the rod |02, clevis I,08, lever fbearing $2, the spring 92 .will yield and Aallow the rod 88 to move further'until the head 96 is seated.

While in the exempliiication of the invention herein disclosed, the electric circuits are broken and the motor unclutched coincidentally with the mechanical arresting of gun declination as a function of gun movement in azimuth, any device will be considered within the scope of this invention whether the electric circuits are thus broken or not and whether the motor is thus unclutched or not.

In the embodiment of the invention herein disclosed, the cam 54 has a single high point which limits down tilt of the guns to the position l5 only when the guns are pointed directly aft. It will be apparent, that additional raised fulcrum points may be spaced around the cam to limit downward tilt of the guns in other than the aft position. The contour of the cam thus delineates the contour of the line of nre of the guns.

Having thus described an embodiment of my invention, I claim:

1. In a device for controlling an aircraft gun turret of the class having electric power means for moving the guns in elevation or declination, means for moving the guns in azimuth, and stop means for limiting gun movement in declination as a function of turret rotation in azimuth, the improvement in stop means which comprises a cam carried on said turret, gearing carried on said turret operative by movement of said turret in azimuth to rotate said cam, a lever of the rst class fulcrumed on said cam, means on the power end of said lever engageable by the means for moving the gun in declination, a stop for the work end of said lever, and means connected to the work end of said lever operative by movement of the power end to disconnect the electric circuit of the power means when said work end means is moving into contact with said stop.

2. The combination in an aircraft gun turret of the type having an electric motor and an electric motor operated means for moving the guns in elevation or declination, means for moving the guns in azimuth, and stop means for limiting gun movement in declination as a function of turret rotation in azimuth, the improvement in stop means which comprises a cam carried on said turret, gearing carried on said turret operative by movement of said turret in azimuth to rotate said cam, a lever of the rst class having its fulcrum on the working surface of said cam, linkage connesting the power end of said lever to said electric power operated means whereby movement of said guns in declination rocks said lever on said fulcrum, a stop for the work end of said lever, and means operative by movement of said work end to said stop to mechanically disconnect said electric motor from said electric motor operated means and to electrically break the circuit to said motor.

3. For use in connection with an aircraft gun turret of the type which includes an electric motor.

electric :motor operated .means for moving lthe guns in elevation-or'linsdeclinationfasecond: electric Ymotorsfor moving fthe :gunsin Lazimuth, Iand stop means lforlin-uitingA gun movement in .declinations-asa function-of turret rotation in azimuth, the irriprovement in stop means which comprises `a rotatable :cam carried Eby said turrent, gearing Vcarril-:fd `:by Jsaidturre't operative 'by movement of tsaidturret'in gazimu'thto rotate Vsaid cam, a lever of ithe class having Yfulcrum 'on vthe working :surface fofi'saidv cam, linkage-connecting theupower end of said lever to said electric motor operated fmeans wl'iere'byimovernentfofv said guns zindeclination rocksis'aid flereron @said-fulcrum, a stop A.for Vthe werkend of said iever, arelay normally completing the nrstisaiid motor circuit and a iiring circuit, .andmeans Loperative by movement of the work end of said lever to said stop to mechanically disconnect the first said electric motor from said electric motor operated means and to operate said relay to break the circuit to the first said motor and to the iiring circuit.

4. For use in connection with an aircraft gun turret of the type in which the guns may be moved in elevation or declination, or in azimuth, said type including stop means for limiting gun movement in declination as a function of turret rotation in azimuth, an electric motor having two circuits for rotation in opposite directions, a firing circuit, electric motor operated means operable by said electric motor in one or the other direction for moving the gun in elevation or in declination, and a second electric motor for moving the gun in azimuth, the improvement which comprises a rotatable cam carried by the turret, gearing carried by said turret operable by movement of said turret by said second electric motor in either direction in azimuth to rotate said cam, a lever of the first order adapted to fulcrum on Some part of the working surface of said cam depending on the azimuth position of said turret, linkage connecting the power end of said lever to said electric motor operated means whereby movement of said guns in declination rocks said lever on said fulcrum, a rod joined to the work end of said lever, a spring-cushioned stop for arresting movement of said rod to thereby limit declination of said gun, clutch means operable by movement of said rod to disengage the rst said motor from said electric motor operable means, and switch means operable by movement of said rod to open the firing circuit and to open that circuit of the first said electric motor which rocks the guns in declination.

l5. In a device for controlling an aircraft gun turret of the class which includes means rotatable for moving the gun in declination, means rotatable for moving the gun in azimuth, and means to arrest gun movement at a predetermined degree of declination when the gun is positioned at a predetermined point in azimuth, the improvement in arresting means which comprises a lever, connecting linkage joining the means rotatable for moving the gun in declination to the power end of said lever, an arresting member operatively joined to the work end of said lever, a Xed mechanical stop associated with said arresting member for arresting movement of said arresting member at the extreme end of its travel, a cam adjacent said lever intermediate its power and work ends, fulcrum points of different predetermined heights for said lever around the periphery of said cam, and power transmitting means connecting said cam for rotation by said means rotatable for moving the gun in azimuth,

V,sandales constructed that movement of said arresting mem- 10 ber to said xed mechanical stop disengages said clutch.

7. The device of claim 6 with an electric switch associated with said lever and operable by said lever tothe open position upon movement of said 15 arresting member to the fixed mechanical stop. PAUL E. HUMPHREY.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date v2,400,385 Blaylock May 14, 1946 2,409,406 Trotter Oct. 15, 1946 2,415,967 Pontius Feb. 18, 1947 2,434,653 HOlSChuh et al Jan. 20, 1948 2,434,654 Watkins et al J an. 20, 1948 

